Colored Razor Blades

ABSTRACT

Colored razor blades are provided. Methods for manufacturing such blades are also provided, including methods involving depositing an oxide coating prior to heat treatment of the blade material and heat treating under conditions selected to enhance the color of the coating.

This application is a continuation of U.S. application Ser. No.10/860,928, filed Jun. 3, 2004 and is pending.

TECHNICAL FIELD

This invention relates to razor blades and processes for manufacturingrazor blades, and more particularly to colored razor blades.

BACKGROUND

Razor blades are typically formed of a suitable metallic sheet materialsuch as stainless steel, which is slit to a desired width andheat-treated to harden the metal. The hardening operation utilizes ahigh temperature furnace, where the metal may be exposed to temperaturesgreater than 1100° C. for up to 10 seconds, followed by quenching.

After hardening, a cutting edge is formed on the blade. The cutting edgetypically has a wedge-shaped configuration with an ultimate tip having aradius less than about 1000 angstroms, e.g., about 200-300 angstroms.

Various coatings may be applied to the cutting edge. For example, hardcoatings such as diamond, amorphous diamond, diamond-like carbon (DLC)material, nitrides, carbides, oxides or ceramics are often applied tothe cutting edge or the ultimate tip to improve strength, corrosionresistance and shaving ability. Interlayers of niobium or chromiumcontaining materials can aid in improving the binding between thesubstrate, typically stainless steel, and the hard coatings. Apolytetrafluoroethylene (PTFE) outer layer can be used to providefriction reduction.

It is important that these coatings be applied, and any otherpost-hardening processing steps be performed, under sufficiently lowtemperature conditions so that the hardened, sharpened steel is nottempered. If the steel is tempered it will lose its hardness and may notperform properly during use.

Examples of razor blade cutting edge structures and processes ofmanufacture are described in U.S. Pat. Nos. 5,295,305; 5,232,568;4,933,058; 5,032,243; 5,497,550; 5,940,975; 5,669,144; EP 0591334; andPCT 92/03330, which are hereby incorporated by reference.

SUMMARY

The present invention provides razor blades that include a coloredcoating, i.e., a coating having a color different from the color of theunderlying blade material. The term “colored” as used herein, includesall colors, including black and white. The colored coating provides adesirable aesthetic effect, without deleteriously affecting theperformance or physical properties of the blade. The color of the razorblades can be color-coordinated with the color of the housing of a razorcartridge or the handle or other components of a shaving system. In somepreferred implementations, the coating covers substantially the entireblade surface, enhancing the aesthetic effect and simplifyingmanufacturing. The coatings are durable, exhibit excellent adhesion tothe blade material, and can be produced consistently and relativelyinexpensively.

In one aspect, the invention features a razor blade for use in a wetshaving system, including a blade formed of a metallic sheet materialand having a sharpened cutting edge, and a colored coating disposed onat least a portion of the blade.

Some implementations may include one or more of the following features.The colored coating covers substantially the entire blade. The coatingincludes a metallic oxide, and/or metallic oxynitride, e.g., titaniumoxide, and/or other transition metal oxides including zirconium,aluminum, silicon, tungsten, tantalum, niobium, iron, and mixturesthereof. The metallic sheet material comprises stainless steel, e.g.,martensitic stainless steel. The coating has a color selected from thegroup consisting of gold, violet, green and blue. The coating has athickness of from about 300 to 10,000 Angstroms, e.g., from about 600 to2400 Angstroms.

The method may include additional steps. For example, the method mayfurther include heating the blade material prior to or during theapplying step and/or ion bombardment of the blade material prior to orduring the applying step.

The invention also features methods of producing colored coatings thatdo not deleteriously affect the final properties of the blade. Forexample, in one aspect the invention features a method that includesapplying an oxide coating to a blade material, subjecting the coatedblade material to a hardening process, and forming the hardened coatedblade material into a razor blade, the oxide coating providing the razorblade with a colored coating.

In some preferred methods, the coating is applied to a relatively largesheet of metal, from which a great many blades can be manufactured. Forexample, the applying step may be performed on a sheet of blade materialhaving a width substantially greater than the width of the razor blade.In this case, the method may further include, between the applying andsubjecting steps, slitting the blade material to form a plurality ofstrips. Some methods involve a substantially continuous coating andheat-treating process. The method may also include controlling thehardening process so that the composition of the oxide coating ischanged by the hardening process.

Some methods may include one or more of the following features. Thecontrolling step includes controlling the ambient conditions under whichthe hardening process is performed. For example, the controlling stepmay include providing a chamber within which the hardening process isperformed, and introducing one or more gases to the chamber during thehardening process. The gases are selected from the group consisting ofnitrogen, hydrogen, and oxygen, carbon monoxide, carbon dioxide,nitrogen oxide, nitrogen dioxide, water vapor, and mixtures thereof.

The hardening process includes passing the blade material through afirst temperature zone which reduces the oxide coating and a secondtemperature zone which oxidizes the coating. The hardening process isperformed in a tunnel oven, and the first temperature zone is a firstzone of the tunnel oven and the second temperature zone is a second,shorter zone of the tunnel oven in which the temperature can becontrolled independently of the temperature in the first zone of thetunnel oven. The oxygen partial pressure in the second zone of thetunnel oven can be controlled independently of the ambient conditions inthe first zone of the tunnel oven. By controlling the oxygen partialpressure in the second zone of the tunnel oven, the desired color of theoxide film may be further targeted and controlled. The hardening processmay result in martenization of the blade material.

In some methods, the forming step includes sharpening the blade materialto form a cutting edge. The forming step may also include breaking theslitted blade material into portions having substantially the samelength as the razor blade.

The method further includes applying a coating to the cutting edge toenhance the shaving performance of the cutting edge. The coating isselected from the group consisting of chromium containing materials,niobium containing materials, diamond coatings, diamond-like coatings(DLC), nitrides, carbides, oxides, and telomers. The method furtherincludes selecting the stoichiometry composition of the oxide coating soas to give a desired final color.

In a further aspect, the invention features a wet shaving system thatincludes a razor including a blade formed of a metallic sheet materialand having a sharpened cutting edge, the blade having a colored coatingdisposed on at least a portion of the blade. The blade may include anyof the features discussed above.

The term “colored,” as used herein, refers to a coating having a colorthat is different from the color of the uncoated substrate material towhich the coating is applied.

The term “colorized coating,” as used herein, refers to a coloredcoating that has been heat treated to enhance its coloration.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features andadvantages of the invention will be apparent from the description anddrawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a top view, and FIG. 1A is a side view of a supported razorblade.

FIG. 2 is a perspective view of a shaving razor including the FIG. 1razor blade.

FIG. 3 is a flow diagram showing steps in a razor blade manufacturingprocess according to one embodiment of the invention.

FIG. 4 is a temperature profile for a hardening furnace.

FIG. 5 is a diagrammatic side view of an oxidization zone.

FIG. 5A is a diagrammatic cross-sectional view of a sparger, taken alongline A-A in FIG. 5.

FIG. 5B is a side view of the sparger shown in FIG. 5A.

FIG. 5C is a front view of an exit gate used with the oxidation zoneshown in FIG. 5.

DETAILED DESCRIPTION

Referring to FIGS. 1 and 1A, razor blade 10 includes a stainless steelsubstrate, which typically has a thickness of about 0.003 to 0.004 inch.The stainless steel has been hardened to its martensitic phase. Theblade 10 has a cutting edge 14 (sometimes referred to as the “ultimateedge” of the blade) that has been sharpened to a tip 16. Preferably, tip16 has a radius of less than 1,000 angstroms, preferably 200 to 400angstroms, measured by SEM. Typically, tip 16 has a profile with sidefacets at an included angle of between 15 and 30 degrees, e.g., about 19degrees, measured at 40 microns from the tip.

Blade 10 includes a very thin, e.g., 300 to 10,000 Angstrom, coloredcoating. This coating is not visible in FIGS. 1 and 1A due to the scaleof these figures. The colored coating is preferably formed of an oxidethat is selected and applied so as to provide a desired color to thefinished blade, and to withstand the high temperature hardening processand other blade processing steps without a deleterious color change orother damage or deterioration.

Suitable oxides include oxides of titanium and other transition metals,such as zirconium, aluminum, silicon, tungsten, tantalum, niobium, iron,and mixtures of these oxides.

Referring to FIG. 2, blade 10 can be used in shaving razor 110, whichincludes a handle 112 and a replaceable shaving cartridge 114. Cartridge114 includes housing 116, which carries three blades 10, a guard 120 anda cap 122. Each blade 10 is welded to a support 11, and the blades 10and their supports 11 are movably mounted, as described, e.g., in U.S.Pat. No. 5,918,369, which is incorporated herein by reference. Cartridge114 also includes an interconnect member 124 on which housing 116 ispivotally mounted at two arms 128.

As discussed above, the color of the blade may be coordinated with thecolor of the housing or handle, or a portion of the housing or handle,to create a pleasing and distinctive aesthetic effect. For example, thecolor of the coating may be the same as, and/or contrasting orcomplementary with the color(s) of the housing and/or handle. The colorof the coating may also be coordinated with that of elastomeric portionsof the cartridge, e.g., the guard.

Blade 10 can be used in other types of razors, for example razors havingone, two or three or more blades, or double-sided blades. Blade 10 canbe used in razors that do not have movable blades or pivoting heads. Thecartridge may either be replaceable or be permanently attached to arazor handle.

A suitable process for applying the colored coating and manufacturingthe razor blade is shown diagrammatically in FIG. 3. As shown in FIG. 3,preferably, the oxide layer is applied to the sheet material from whichthe blade is formed, prior to the slitting of the sheet material to adesired width that is typically significantly wider than the final bladewidth. Performing the coating step at this stage simplifiesmanufacturing, because a large surface area can be coated at once. Theoxide coating is applied to a sheet of soft blade steel, e.g., byphysical vapor deposition (PVD), plasma enhanced chemical vapordeposition (PECVD), or other deposition technique, in a layer of uniformthickness. The layer is typically about 400 to 10,000 Angstroms, forexample about 500 to 800 Angstroms. The substrate may be heated prior toand/or during deposition, e.g., to a temperature of about 100° C. to350° C. Heating the substrate in this manner may increase the adhesionand wear resistance of the oxide coating. The oxide coating may bedeposited on top of a thin adhesion-promoting layer of a non-oxidizedmetal, e.g., chromium, titanium, or other non-oxidized metals. Thisadhesion-promoting layer may be applied to the sheet of soft bladesteel, e.g., by physical vapor deposition (PVD), and can have thicknessof between 50 and 250 angstroms. If desired, the coating may bepre-applied by a supplier, prior to the other processing steps shown inFIG. 3. The oxide coating can be deposited by a number of techniques,including evaporation (a PVD technique), sputtering (PVD), arc sources(PVD), plasma enhanced chemical vapor deposition (PECVD), and othertechniques such as sol-gel processing, and thermal growth of films. Theprocess parameters to be used will depend upon the technique and toolingused, and are selected so as to produce an oxide layer having thedesired thickness and other properties.

After the coating is applied, the sheet material is slit into strips,and the strips are perforated for ease of handling during subsequentprocessing. Other pre-hardening steps, such as scoring, may beperformed, if desired.

When the desired sequence of pre-hardening steps has been completed, theblade material is subjected to a hardening process, which results inmartensitic transformation of the stainless steel. A typical temperatureprofile for the hardening process, which is conducted in a tunnel oven,is shown in FIG. 4. This temperature profile within the oven involvesquickly ramping the temperature of the material up to a hightemperature, e.g., approximately 1160° C., maintaining the material atthis temperature for a period of time, during which austenization of thestainless steel occurs. After the material exits the oven, it is rapidlyquenched, causing martenization of the stainless steel.

The processes described below may be added to existing blade steelhardening processes. Advantageously, in many cases the colorizationprocesses described herein can be integrated into an existing hardeningprocess with minimal changes to the existing process. One existing bladesteel hardening process utilizes a high temperature furnace (greaterthan 1100° C.) containing a flowing Forming Gas (a mixture of hydrogenand nitrogen) ambient. Two parallel continuous stainless steel bladestrips are pulled through this high temperature furnace at 36.6 m/min(120 ft/min) each. This high temperature treatment is used toaustinitize the stainless steel strips. Near the exit of the hightemperature furnace is a water-cooled jacketed tube (also referred to asthe water-cooled muffle tube). This section is used to start the coolingprocess of the stainless steel blade strips. Just after the water-cooledzone, the stainless steel blade strips are pulled through a set ofwater-cooled quench blocks. The quench blocks initiate the martensitictransformation of the steel.

During the hardening process, the oxide coating is “colorized,” i.e.,the coloration of the oxide coating is enhanced and/or changed.Colorization may result in an enhancement of the color, for example to abrighter shade or more brilliant appearance, and/or may result in achange of the color of the coating to a different color, e.g., fromblue-gray to violet, gold, or blue, or from dull-green to brightgreen-yellow, dark green, or blue-green. This colorization results froma change in the refractive index of the coating, which in turn resultsfrom a change in the composition, stoichiometric composition, and/or thecrystalline structure of the oxide coating. The degree of change in theapparent film index of refraction will control the color of thecolorized film.

The composition and crystalline structure of the coating aftercolorization, and thus the final color of the coating, will depend onseveral variables. For example, the composition, or stoichiometry, ofthe coating will depend on the gases that are present in the furnaceduring the hardening procedure. Introducing only nitrogen into thefurnace will generally change an initially gray-blue colored titaniumoxide coating to bright blue or blue-violet. This color change is due toa reduction in the oxygen content of the titanium oxide coating. If airand/or moisture is introduced to the furnace, the reduction in theoxygen content of the titanium oxide coating is much less, and theresulting index of refraction is higher.

Other variables that affect colorization are the initial thickness andcomposition of the oxide coating, the temperature profile of thehardening furnace, and the speed at which the material travels throughthe furnace. If the thickness and/or composition of the coating varyover the length of the material, it may be necessary to adjust theprocess parameters of the hardening process in order to obtain aconsistent end product. Because it is difficult to rapidly adjust thetemperature and ambient conditions in the large tunnel ovens that aretypically used for hardening, it may be desirable to provide a separate,shorter oven that is more rapidly adjustable (referred to below as “theOxidation Zone”). Thus, the conventional, large tunnel oven may be usedfor the high temperature step of the hardening operation and to slightlyreduce the oxide coating (which may also increase the uniformity of itscomposition), and the additional, shorter oven may be used foroxidation/colorization, providing an oxidization zone in which the gascomposition can be relatively quickly adjusted to compensate forvariations in the material. The strip temperature in this OxidizationZone, and hence the coloration ambient responsiveness, can be adjustedup or down, by adjusting the set point of the last zones of the hightemperature furnace. The composition and/or flow rate of the gas(es)introduced to the Oxidization Zone can then be altered, based on theappearance of the material as it exits the Oxidation Zone and quenchingarea.

Other processes may be used to obtain colorized coatings using theoxides discussed above, particularly titanium oxide (or anystoichiometry of oxidized titanium), as the thin film. In theseprocesses, either the ambient conditions (composition and temperature)within the high temperature furnace and/or the Oxidation Zone areadjusted to control the color of the colorized coating.

The Oxidation Zone, when utilized, is located between the hightemperature furnace and the first set of water-cooled quench blocks, andreplaces the water-cooled muffle tube used on a standard hardening line.The furnace temperature profile may be modified so that the coatedstainless steel blade strips emerge from the hardening furnace and enterthe Oxidation Zone at a temperature near or below 1160° C. Addition ofheating elements to the Oxidation Zone may also be employed to improvethe stability of the process, such as during start-up.

The Oxidation Zone may be, for example, an Inconel tube attached to thetubing used in the high temperature furnace of the hardening line.Referring to FIG. 5, in one embodiment a gas sparger system 200 isinstalled about 2.9 cm from the entrance of the tube 202 and dimensionedto extend 5.1 cm down the tube. In this case, the sparger has a total of16 inlet gas ports (not shown), and is designed so that gas injectedthrough the sparger (arrows, FIG. 5A) will uniformly impinge upon thestainless steel strips. Gas is introduced to the sparger through a pairof inlet tubes 201, 203. A gas baffle 204 may be included so that thetwo stainless steel strips of blade material are separated from eachother so that the gas composition on each side of the baffle may beindependently controlled. The baffle 204 may define two chambers 210,212, as shown in FIG. 5A. In this case, the gas baffle may, for example,begin 0.3 cm from the entrance of the Oxidation Zone and extend down thetube 10.2 cm. If desired, the gas baffle may extend along the entirelength of the Oxidation Zone. The gas sparger is designed so that dualgas flow control is possible, allowing two strips to be processed at thesame time, using the same furnace. Gas flow rates may be controlledusing gas flow meters. The exit of each chamber of the Oxidation Zonemay be equipped with a flange and two pieces of steel 218 which define aslit 219 and thereby act as an exit gate 220 (FIG. 5C). The slit may be,for example, 0.1 to 0.2 cm wide. This exit gate prevents any back-flowof ambient air into the Oxidation Zone and also encourages better mixingof the gases within the Oxidation Zone. As discussed above, just afterthe Oxidation zone, the stainless steel blade strips are pulled througha set of water-cooled quench blocks 206. The quench blocks initiate themartensitic transformation of the steel.

The oxidation gas, for example a mixture of oxygen and nitrogenintroduced as dry air and nitrogen, may be used to control thecoloration process, in which case it is added directly to the flow ofgases from the high temperature furnace.

All of the processes described above allow a decorative transition metaloxide film to be specially modified (colorized) during the hardeningprocess of a martensitic stainless steel. If, instead, a decorativetransition metal oxide film were colorized prior to the hardeningprocess, it would generally be degraded during the standard hardeningprocess. If a coloration process were employed after the martensitictransformation, it would generally either destroy the martensiticproperties of the stainless steel strip, or would require extensivetemperature control and special material handling. The processesdescribed above generally provide highly adherent, protective oxides,while allowing excellent color control and without detrimentallyimpacting the metallurgic properties of the hardened stainless steelblade strips.

After the hardening process, the blade material is sharpened, to createthe cutting edge shown in FIG. 1, and the strip of blade material isbroken into blades of the desired length. The blades may then be welded,e.g., using laser welding, to the support 11 (FIG. 2), if such a supportis to be used.

In addition to the colored coating, the razor blade may include otherfeatures, such as performance enhancing coatings and layers, which maybe applied between the sharpening and welding steps.

For example, the tip may be coated with one or more coatings, asdiscussed in the Background section above. Suitable tip coatingmaterials include, but are not limited to, the following:

Suitable interlayer materials include niobium and chromium containingmaterials. A particular interlayer is made of niobium having a thicknessof from about 100 to 500 angstroms. PCT 92/03330 describes use of aniobium interlayer.

Suitable hard coating materials include carbon-containing materials(e.g., diamond, amorphous diamond or DLC), nitrides (e.g., boronnitride, niobium nitride or titanium nitride), carbides (e.g., siliconcarbide), oxides (e.g., alumina, zirconia) and other ceramic materials.Carbon containing hard coatings can be doped with other elements, suchas tungsten, titanium or chromium by including these additives, forexample, in the target during application by sputtering. The hardcoating materials can also incorporate hydrogen, e.g., hydrogenated DLC.DLC layers and methods of deposition are described in U.S. Pat. No.5,232,568.

Suitable overcoat layers include chromium containing materials, e.g.,chromium or chromium alloys that are compatible withpolytetrafluoroethylene, e.g., CrPt. A particular overcoat layer ischromium having a thickness of about 100-500 angstroms.

Suitable outer layers include polytetrafluoroethylene, sometimesreferred to as a telomer. A particular polytetrafluoroethylene materialis Krytox LW 1200 available from DuPont. This material is a nonflammableand stable dry lubricant that consists of small particles that yieldstable dispersions. It is furnished as an aqueous dispersion of 20%solids by weight and can be applied by dipping, spraying, or brushing,and can thereafter be air-dried or melt coated. The layer is preferably100 to 5,000 angstroms thick, e.g., 1,500 to 4,000 angstroms. Providedthat a continuous coating is achieved, reduced telomer coating thicknesscan provide improved first shave results. U.S. Pat. Nos. 5,263,256 and5,985,459, which are hereby incorporated by reference, describetechniques which can be used to reduce the thickness of an appliedtelomer layer.

For example, the razor blade tip may include a niobium interlayer, a DLChard coating layer, a chromium overcoat layer, and a Krytox LW1200polytetrafluoroethylene outer coat layer.

The following examples are intended to be illustrative and not limitingin effect.

GENERAL COLORIZED COATING PROCESS SET-UP, EXAMPLES 1-4

In the following examples, Examples 1-4, samples of a stainless steelsheet material having a 650 Angstrom coating of titanium oxide were heattreated in a high temperature furnace with hardening temperatureprofiles shown in FIG. 4. The exit of the high temperature furnace wasequipped with an Oxidation Zone (Examples 1-3 only). The temperatureprofile of the high temperature furnace, as well as the gas ambient ofthe high temperature furnace, was controlled. Gases were also introducedto the Oxidation Zone in the final steps of the colorized coatingprocess (Examples 1-3 only). The temperature in the high temperaturefurnace was set at 1160° C., and the last of the four zones (the exittemperature) was set at 1060° C.

Example 1 Nitrogen in High Temperature Furnace; Dry Air in OxidationZone Used for Color Control

In this experiment, the high temperature furnace maintained thetemperature profile shown in FIG. 4. The ambient within the hightemperature furnace was flowing nitrogen (18.9 liters/min). The coatedstainless steel sheet material was pulled through the furnace at 36.6m/min (120 ft/min). A controlled mixture of nitrogen (1 liter/min) anddry air (0 to 225 ml/min) was introduced to each side of the OxidationZone. The amount of air introduced to the Oxidation Zone established thefinal color of the colorized coating. The initial color of the sampleswas blue-gray. With no air flow to the Oxidation Zone, the final colorwas violet. As the air flow rate was increased to 25 ml/min, the colorbecame a deep blue. At air flow rates greater than 200 ml/min, the colorwas a light blue. Use of the Oxidation Zone allowed for a rapidlyresponding coloration process, allowing for on-line color control. Inthis process, it is believed that the initial titanium oxide film wasboth densified and reduced, decreasing the apparent film index ofrefraction within the high temperature furnace. As the hot film waspulled through the Oxidation Zone, the increased oxygen ambientre-oxidized the film, increasing the apparent film index of refractionand thereby colorizing the film.

Example 2 Forming Gas in High Temperature Furnace; Dry Air in OxidationZone Used for Color Control

The high temperature furnace contained an ambient of flowing Forming Gas(75% hydrogen, 25% nitrogen). Flow rates were set between 4.7 liters/minand 18.9 liters/min. A controlled mixture of nitrogen (1 liter/min) anddry air (0 to 225 ml/min) was introduced to each side of the OxidationZone. The amount of air introduced to the Oxidation Zone established thefinal color of the colorized coating. In this process, it is believedthat the initial titanium oxide film was densified, reduced, andslightly nitrated. These changes decreased the apparent film index ofrefraction of the oxide film while the film was within the hightemperature furnace. As the hot film was pulled through the OxidationZone, the increased oxygen ambient re-oxidized the film, increasing theapparent film index of refraction and modifying the color of the film.The process responsiveness and color variability, for a given filmthickness, were reduced relative to the responsiveness and variabilityobserved during the experiment described in Example 1.

Example 3 Forming Gas and Nitrogen in High Temperature Furnace; Dry Airin Oxidation Zone Used for Color Control

In this experiment, the process parameters were the same as thosedescribed above for Example 2, except that nitrogen was added to theForming Gas flow to decrease the overall hydrogen content. The FormingGas flow was reduced to between 25% and 75% of the total gas flow withinthe high temperature furnace. The process color variability, for a givenfilm thickness and range of air flow rates to the Oxidation Zone, wassignificantly reduced relative to the processes utilizing only FormingGas or only Nitrogen in the High Temperature Furnace.

Example 4

Forming Gas and/or Nitrogen in High Temperature Furnace; Dry Air in HighTemperature Furnace Used for Color Control; Oxidation Zone not used forColor Control

In this experiment, the high temperature furnace contained an ambient offlowing Forming Gas (75% hydrogen, 25% nitrogen), nitrogen, and dry air.Each of the flow rates of the Forming Gas and nitrogen varied between 0liters/min and 18.9 liters/min; with the total flow rate of Forming Gasplus nitrogen being between 4.7 liters/min and 18.9 liters/min. Dry airflow rates varied between 0 and 225 ml/min. No air or nitrogen was addedto the Oxidation Zone, which was, in this experiment, a water-cooledjacketed muffle tube. The amount of air introduced to the front end ofthe high temperature furnace established the final color of thecolorized coating. In this process, the oxidation state, and hence theapparent film index of refraction, was controlled by controlling theoxidation-reduction driving force within the high temperature furnace.This process allowed for a wider range of color control, relative toExamples 1-3.

Other embodiments are within the scope of the following claims. Forexample, while it is generally preferred, for ease of manufacturing,that the oxide coating be applied prior to slitting and perforation, thecoating may be applied at any point in the manufacturing process priorto hardening. Moreover, in some processes the perforating and/or weldingstep(s) shown in FIG. 3 may be omitted. Other process steps may be addedif desired, for example a scoring operation may be performed prior toperforation.

1. A razor blade for use in a wet shaving system, comprising: a bladeformed of a stainless steel sheet material and having a sharpenedcutting edge wherein said material has been a) heated to a hightemperature, b) austenized under a forming gas, and c) while still underthe forming gas, its temperature lowered prior to oxidation; and acolored coating disposed on at least a portion of the blade wherein saidcolored coating is formed from oxidizing and quenching the material andwherein said coating comprises a metallic oxide and/or a metallicoxynitride.
 2. The razor blade of claim 1 wherein said colored coatingcovers substantially the entire blade.
 3. The razor blade of claim 2wherein said oxidized colored coating consists of titanium oxide, and/orother transition metal oxides including zirconium, aluminum, silicon,tungsten, tantalum, niobium, iron, and mixtures thereof.
 4. The razorblade of claim 1 wherein said stainless steel comprises martensiticstainless steel.
 5. The razor blade of claim 1 wherein said coating hasa color selected from the group consisting of gold, violet, green andblue.
 6. The razor blade of claim 1 wherein said coating has a thicknessof from about 300 to 10,000 Angstroms.
 7. The razor blade of claim 6wherein said coating has a thickness of from about 600 to 2400Angstroms.
 8. A wet shaving system, comprising: a razor including ablade formed of a stainless steel sheet material and having a sharpenedcutting edge wherein said material has been a) heated to a hightemperature, b) austenized under a forming gas, and c) while still underthe forming gas, its temperature lowered prior to oxidation, the bladehaving a colored coating disposed on at least a portion of the bladewherein said colored coating is formed from oxidizing and quenching thematerial and wherein said coating comprises a metallic oxide and/or ametallic oxynitride.
 9. The shaving system of claim 8 wherein saidcolored coating covers substantially the entire blade.
 10. The shavingsystem of claim 8 wherein said oxide consists of titanium oxide, and/orother transition metal oxides including zirconium, aluminum, silicon,tungsten, tantalum, niobium, iron, and mixtures thereof.
 11. The shavingsystem of claim 8 wherein said stainless steel comprises martensiticstainless steel.
 12. The shaving system of claim 8 wherein said coatinghas a color selected from the group consisting of gold, violet, greenand blue.
 13. The shaving system of claim 12 wherein said coating has athickness of from about 300 to 10,000 Angstroms.
 14. The shaving systemof claim 13 wherein said coating has a thickness of from about 600 to2400 Angstroms.